The IEEE 25GBase-KR 25GbE interface is an interface for backplane Ethernet that meets the increasing bandwidth requirements in the I/O area of blade servers and edge servers. It is a 25-Gigabit interface for point-to-point connections across backplane PCB traces.
The 25GbE interface uses the Physical Coding Sublayer( PCS) and the Physical Media Attachment( PMA) and a sublayer for autonegotiation. 25GBase-KR is largely equivalent to the 10GBase-KR interface specified by the IEEE 802.3by working group. The bridgeable distance is one meter, the connection is made via one lane across the backplane PCB with a data rate of 25 Gbps. 25GBase-KR has 64B66B coding and differential output levels between 800 mV and 1.2 V.